Impact of nanostructuring on the enthalpy of formation of metal hydrides

被引：105

作者：

Berube, Vincent ^{[1
]}

Chen, Gang ^{[2
]}

Dresselhaus, M. S. ^{[1
]}

机构：

[1] MIT, Dept Phys, Cambridge, MA 02139 USA

[2] MIT, Dept Mech Engn, Cambridge, MA 02139 USA

来源：

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY | 2008年 / 33卷 / 15期

关键词：

hydrogen storage; nanotechnology; nanostructure; enthalpy; thermodynamics; excess volume; metal hydride;

D O I：

10.1016/j.ijhydene.2008.05.083

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

High-energy ball milling has been shown to decrease the release temperature, increase the reaction kinetics, and lower the enthalpy of formation of metal hydrides in certain cases. This paper discusses several potential mechanisms for the reduction of the enthalpy of formation. Although the increased surface and grain boundary energy could play a role in reducing the enthalpy of formation, the predicted magnitude is too small to account for experimental observations. Structural deformation and the associated volume change provide another mechanism for the change in this thermodynamic property. We employed three equations of state models to characterize the excess energy present in the deformed regions and found that the excess volume provides a plausible explanation for the experimentally observed change in thermodynamic properties. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

引用

页码：4122 / 4131

页数：10

共 23 条

[1] POLYMORPHISM OF MAGNESIUM HYDRIDE AT HIGH-PRESSURE [J].